ABSTRACT Support is requested for a Keystone Symposia conference entitled Cancer Immunotherapy: Combinations, organized by Drs. Chris Boshoff, Lieping Chen and Lisa Coussens. The conference will be held in Montreal, Quebec from March 23-27, 2018. By 2025, most patients with cancer will receive immunotherapy as part of their treatment regimen. This symposium will cover the most critical topics integral to this vision: How can we integrate, sequence or combine immunotherapy with standard-of-care cytotoxic therapy, radiotherapy and targeted therapies? Which preclinical models are best predictive of combination approaches? How do we combine immune agonists as well as molecules inhibiting immune-suppressive pathways with checkpoint inhibitors? What are the rational combinations for cancer vaccines and viro-therapy? Which combinatorial approaches could prevent or treat adaptive mechanisms of resistance? Most immunotherapies are being developed in isolation, or being tested as single agents in preclinical models or in clinical studies. This meeting helps to address the gaps in knowledge of how and when to combine therapies, and how to integrate immunotherapy into current standard- of-care or novel targeted therapy approaches ? both preclinical and clinical. Overall, the objectives of this meeting are to: 1) Elucidate rational combinations for immunotherapy; 2) Discuss preclinical and other models to inform combinatorial approaches; 3) Understand the relevance for biomarker approaches; and 4) Provide insights into the latest preclinical and clinical data for immunotherapy combinations.